According to conventional structure of motor vehicles, the engine is connected to the wheels through the clutch, transmission gear, propeller shaft and differential gear. Therefore, when a driver runs his car, a noise takes place due to engagement of gears, and the transmission fails to reach an efficient gear ratio due to a speed change in the transmission gear, which results in lots of energy loss. Moreover, an increase in the weight of the car body is caused by equipping it with many parts, such as the transmission gear, propeller shaft, differential gear, etc., and a change of speed must be made by operating both the transmission gear and the clutch. Even when the car is stopped, the clutch and the brake must be operated simultaneously in order to reduce the propulsive force of the power transmitted. For this reason, there are disadvantages and problems in that beginners in driving are unable to learn the driving techniques in a short time. Even though the driver is skilled, he has always to operate simultaneously the clutch and the transmission gear, and the clutch and the brake during running or at the time of stopping, so that he must perform these operations at all times and it causes an increase of fatigue. Frequent operation of the speed change reduces attention to safe driving so that it might give rise to an accident.
The invention is generated in an improved form for the purpose of eliminating the above-mentioned disadvantages, and its structure will now described in detail with reference to the accompanying drawings.